The use of a high-speed camera (500 frames/sec) will be used to obtain detailed information concerning the tear film spreading and thickness changes during the blinking process. In addition, lid motion abnormalities, corneal wetting problems, and tear spreading characteristics will be examined. The effectiveness of commercially supplied artificial tear preparations will be evaluated in terms of their ability to duplicate the wetting and spreading properties of natural tears. The movement of contact lenses during blinking may also be investigated.